Methods for coordinating transmission and reception operations of radio modules in a communications apparatus and communication apparatuses utilizing the same

ABSTRACT

A method for coordinating transmission and reception operations of a first and a second radio module in a communications apparatus, the first radio module communicating with a first communications device in a first protocol to provide a first wireless communications service and the second radio module communicating with a second communications device in a second protocol to provide a second wireless communications service. The method includes estimating, by the first radio module, time remaining for the second radio module; receiving, by the second radio module, information regarding the estimated remaining time from the first radio module; determining, by the second radio module, whether time required for the operations of the second radio module exceeds the estimated remaining time; and scheduling, by the second radio module, operations of the second radio module according to the information regarding the estimated remaining time received from the first radio module.

CROSS REFERENCE TO RELATED APPLICATIONS

This Application is a Continuation of co-pending application Ser. No.14/064,342, filed on Oct. 28, 2013, which is a Continuation ofapplication Ser. No. 12/753,195, filed on Apr. 2, 2010, now U.S. Pat.No. 8,599,737, issued on Dec. 3, 2013, which are incorporated byreference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method for coordinating the transmission andreception operations of a plurality of radio modules in a communicationsapparatus, and more particularly to a method coordinating thetransmission and reception operations of a plurality of radio modules ina communications apparatus to avoid traffic collision.

2. Description of the Related Art

With the development of wireless communications technology, mobileelectronic devices may now be provided with more than one wirelesscommunications service, such as a Bluetooth, Wireless Fidelity (Wi-Fi),which is also called wireless local area network (WLAN), and WorldwideInteroperability for Microwave Access (WiMAX) wireless communicationsservice, and so on. In this regard, overlapping or adjacent operatingfrequency bands among the different wireless communications servicescauses transmission performances thereof to degrade. Table 1 below showsthe operating frequency band for a WiMAX, WLAN and Bluetooth wirelesscommunications service.

TABLE 1 Category of Wireless Communications Services WirelessCommunications Usage service Frequency band Wide Area Network (WAN)WiMAX 2.300-2.400 GHz 2.496-2.690 GHz Local Area Network (LAN) WLAN3.300-3.800 GHz 2.412-2.4835 GHz 4.9-5.9 GHz Personal Area Network (PAN)Bluetooth 2.402-2.480 GHz

As shown in Table 1, the frequency bands of WLAN and Bluetooth overlapwith each other. In addition, the frequency bands of WLAN and Bluetoothare adjacent to the frequency bands of the WiMAX. When these wirelesscommunications services are integrated in a mobile electronic devices,simultaneous transmission and reception by different wirelesscommunications services may cause transmission interference. Forexample, the WLAN's frame may be corrupted by the Bluetoothtransmission, and the Bluetooth frames may also be affected if theBluetooth module hops into WLAN's working channels.

Therefore, a method for coordinating the transmission and receptionoperations of a plurality of radio modules in a communications apparatusis highly required.

BRIEF SUMMARY OF THE INVENTION

Communication apparatuses and methods for coordinating transmission andreception operations of at least a first and a second radio module in acommunications apparatus are provided. An embodiment of a communicationapparatus comprises a first radio module communicating with a firstcommunications device in compliance with a first protocol to provide afirst wireless communications service and a second radio modulecommunicating with a second communications device in compliance with asecond protocol to provide a second wireless communications service. Thefirst radio module further estimates time remaining for the second radiomodule before a next operation of the first radio module and transmitsinformation regarding the estimated remaining time to the second radiomodule. The second radio module further schedules operations of thesecond radio module according to the information regarding the estimatedremaining time received from the first radio module.

An embodiment of a method for coordinating transmission and receptionoperations of at least a first and a second radio module in acommunications apparatus is provided, wherein the first radio modulecommunicates with a first communications device in compliance with afirst protocol to provide a first wireless communications service andthe second radio module communicates with a second communications devicein compliance with a second protocol to provide a second wirelesscommunications service, comprising: estimating, by the first radiomodule, time remaining for the second radio module before a nexttransmitting and/or receiving operation of the first radio module;receiving, by the second radio module, information regarding theestimated remaining time from the first radio module; and scheduling, bythe second radio module, operations of the second radio module accordingto the information regarding the estimated remaining time received fromthe first radio module.

A detailed description is given in the following embodiments withreference to the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

The invention can be more fully understood by reading the subsequentdetailed description and examples with references made to theaccompanying drawings, wherein:

FIG. 1 shows a schematic diagram of a multi-radio communications systemaccording to an embodiment of the invention;

FIG. 2 shows a schematic diagram of a multi-radio communications systemaccording to another embodiment of the invention;

FIG. 3 shows an exemplary time chart of the Bluetooth and WLANactivities when the WLAN module always honors the Bluetooth activity;

FIG. 4 shows another exemplary time chart of the Bluetooth and WLANactivities when the WLAN module always honors the Bluetooth activity;

FIG. 5 shows yet another exemplary time chart of the Bluetooth and WLANactivities when the WLAN module always honors the Bluetooth activity;

FIG. 6 shows an exemplary time chart of the Bluetooth and WLANactivities using a remaining window according to an embodiment of theinvention;

FIG. 7 shows a flow chart of a method for coordinating the transmissionand reception operations of a plurality of radio modules in acommunications apparatus according to an embodiment of the invention;

FIG. 8 shows another exemplary time chart of the Bluetooth and WLANactivities using a remaining window according to an embodiment of theinvention;

FIG. 9 shows another flow chart of a method for coordinating thetransmission and reception operations of a plurality of radio modules ina communications apparatus according to another embodiment of theinvention; and

FIG. 10 shows another exemplary time chart of the Bluetooth and WLANactivities using a remaining window according to an embodiment of theinvention.

Table 1 lists a category of Wireless Communications Services.

DETAILED DESCRIPTION OF THE INVENTION

The following description is of the best-contemplated mode of carryingout the invention. This description is made for the purpose ofillustrating the general principles of the invention and should not betaken in a limiting sense. The scope of the invention is best determinedby reference to the appended claims.

Along with the advancements in wireless communications technology, radiomodules providing different wireless communications services may beco-located and coexist in a mobile electronic device. FIG. 1 shows aschematic diagram of a multi-radio communications system according to anembodiment of the invention. The mobile electronic device 100 maycomprise a plurality of radio modules providing different wirelesscommunications services. As an example, the mobile electronic device 100may comprise a Bluetooth module 101 and a WLAN module 102. The Bluetoothmodule 101 may communicate with a Bluetooth device 201 in compliancewith IEEE 802.15 protocol via the air interface. The Bluetooth device201 may be, as an example, a Bluetooth handset. The WLAN module 102 maycommunicate with a WLAN device 202 in compliance with IEEE 802.11protocol via the air interface. The WLAN module 102 may be a Station(STA) and the WLAN device 202 may be, as an example, a WLAN Base Station(BS), Access Point (AP) or Station (STA). FIG. 2 shows a schematicdiagram of a multi-radio communications system according to anotherembodiment of the invention. In the embodiment, the mobile electronicdevice 200 may further comprise a Wimax module 103 communicating with aWimax device 203 in compliance with IEEE 802.16 protocol via the airinterface. The Wimax device 203 may be, as an example, a Wimax BaseStation (BS) or Relay Station (RS). The mobile electronic devices 100and 200 may be a notebook, a cellular phone, a portable gaming device, aportable multimedia player, a Global Positioning System (GPS), areceiver, or others. According to the embodiments, one antenna may bedesigned to be shared among the radio modules 101 and 102 or 101, 102and 103 to improve area efficiency. However, each of the radio modulesmay also individually comprise an antenna to transceive radio signalsand the invention should not be limited thereto. It is also noted thatthe radio modules 101 and 102 or 101, 102 and 103 may be integrated intoan SoC (system on chip) and connected therebetween by internal wires,different but similar bus architectures, or others.

When the radio modules are collocated in a small communicationsapparatus such as the mobile electronic device 100 or 200, a largetransmission power, which is normal, for any radio module may saturatesustainable reception power of other adjacent radio modules and causecorresponding receiving operations for the radio module to fail. FIG. 3shows an exemplary time chart of Bluetooth and WLAN activities when aWLAN module always honors Bluetooth activity. The SCO/eSCO (synchronousconnection oriented/extended synchronous connection oriented) link (alsocalled synchronization link) of a Bluetooth is a symmetric,point-to-point link between a master device and a specific slave device.A master device maintains the SCO/eSCO link by using reserved time slotsat regular intervals. Because the SCO/eSCO link is usually used forreal-time voice transmission, it is preferable for the WLAN module tohonor Bluetooth activity so as to avoid packet lost of the Bluetoothtransmission; especially when there is only one antenna shared betweenthe WLAN and Bluetooth or WLAN and Bluetooth and Wimax modules. Underthis condition, the WLAN module may abort a current transmitting orreceiving operation when traffic collision occurs. As shown in FIG. 3,data packet transmission of Data 2 fails because the WLAN transmission(TX) activity collides with Bluetooth SCO TX activity. Therefore, theWLAN module 102 immediately retransmits Data 2. However, the firstretransmission retry of Data 2 collides again with the Bluetooth SCOreception (RX) activity. Thus, the WLAN module 102 retransmits Data 2one more time. The second retransmission retry of the data packet ofData 2 is successfully transmitted, but the acknowledgement (ACK) fromthe WLAN device 202 (for example, a WLAN AP) is not successfullyreceived (fails) because the WLAN RX activity collides with theBluetooth SCO TX activity. Finally, a third retransmission retry of Data2 is successfully transmitted and the ACK from the WLAN AP is alsosuccessfully received. However, as shown in FIG. 3, the overallthroughput of WLAN module 102 is seriously degraded due to the greatamount of data retransmission, and WLAN bandwidth is not efficientlyutilized.

FIG. 4 shows another exemplary time chart of the Bluetooth and WLANactivities when the WLAN module always honors the Bluetooth activity. Inthis application, the WLAN device 202 (for example, a WLAN AP) transmitsdata packet Data 1 to the WLAN module 102 and receives an ACK therefrom.The WLAN AP next transmits data packet Data 2 to the WLAN module 102,but the WLAN module 102 is unable to reply with an ACK to the WLAN APdue to the SCO TX activity of the Bluetooth module. Next, the WLAN APuses a lower data rate to retransmit the data packet Data 2, but theretransmission still collides with the SCO RX activity of the Bluetoothmodule. Next, the WLAN AP uses a much lower data rate to retransmit thedata packet Data 2 again. However, as the data rate decreases, the timerequired for transmitting the data packet increases and the probabilityof traffic collision also increases. Thus, if the transmission data rateof the WLAN AP decreases to 1 Mbps, probability for failure is almostinevitable. Note that the WLAN AP will disassociate with the WLANstation when all of the retries fail.

FIG. 5 shows yet another exemplary time chart of the Bluetooth and WLANactivities when the WLAN module always honors the Bluetooth activity. Inthis application, the WLAN module 102 enters a power saving (PS) mode tosave battery power. Subsequently, the WLAN device 202 (for example, aWLAN AP) may maintain a continually updated record of the WLAN module102 currently working in the PS mode, and buffer the packets addressedto the WLAN module 102 until the WLAN module 102 specifically requestsfor the packets by sending a polling request (briefly in PS Poll) to theWLAN AP. As shown in FIG. 5, because the WLAN AP transmits the buffereddata packets at an unexpected time after receiving the ACK from WLANstation, it is possible that the transmission of data packets maycollide with the Bluetooth SCO activity. In this case, the WLAN AP wouldretransmit the data packet with a lower data rate. As previouslydiscussed, this trend is not desired as the probability of trafficcollision increases when data rate decreases. Therefore, as shown inFIG. 3 to FIG. 5, the overall throughput of a WLAN module 102 may beseriously degraded due to the repeated data retransmission, and the WLANbandwidth would be inefficiently utilized.

According to an embodiment of the invention, in order to avoid trafficcollision between different radio modules, information regarding aremaining window may be transmitted in advance between different radiomodules so that TX or RX traffic may be properly scheduled according tothe remaining window. The information regarding a remaining window maybe carried in a data packet and transmitted between different radiomodules. As an example, the Bluetooth module 101 may estimate timeremaining for the WLAN module 102 before a next transmitting orreceiving operation of the Bluetooth module 101 and transmit informationregarding the estimated remaining time (i.e. the remaining window) tothe WLAN module 102. After receiving the information regarding timeremaining for a remaining window which the WLAN module 102 can process,the WLAN module 102 may schedule corresponding transmitting or receivingoperations according to the remaining window. In order to clearly andbriefly introduce the concept of using a remaining window, the WLANmodule 102 and the Bluetooth module 101 will be taken as exemplary radiomodules in the following paragraphs. However, it is noted that theconcept of using a remaining window may also be applied to the Wimaxmodule 103 as shown in FIG. 2 and the invention should not be limitedthereto. As an example, the Bluetooth module 101 may estimate timeremaining for the WLAN module 102 and the Wimax module 103, or the Wimaxmodule 103 may estimate time remaining for the WLAN module 102 and theBluetooth module 101, and transmit information regarding the estimatedremaining time therebetween.

FIG. 6 shows an exemplary time chart of the Bluetooth and WLANactivities the remaining window according to an embodiment of theinvention. When finishing a TX or RX activity, the Bluetooth module 101may estimate time remaining for the WLAN module 102 before a nexttransmitting or receiving operation of the Bluetooth module 101 andtransmit information regarding the estimated remaining time (i.e. theremaining window) to the WLAN module 102. As an example, when timebetween the periodic SCO link time slots is 3.75 ms and the SCO TX andRX time slot takes about 1.25 ms, the Bluetooth module 101 may estimatetime remaining for the WLAN module 102 before a next periodic BluetoothSCO TX operation is 2.5 ms (3.75-1.25) and transmit informationregarding a remaining window to the WLAN module 102. After receiving theinformation regarding the 2.5 ms remaining window which the WLAN module102 can process, the WLAN module 102 may first determine whether thetime T1 required for the corresponding TX and/or RX operation exceedsthe remaining window. When the time T1 required for the corresponding TXand/or RX operation does not exceed the remaining window, the WLANmodule 102 may schedule the corresponding TX and/or RX operation withinthe remaining window. As shown in FIG. 6, the date packet Data 1 isarranged to be transmitted within the remaining window and the ACK fromWLAN AP is also successfully received. On the other hand, when the WLANmodule 102 determines that the time T2 required for the TX and/or RXoperation exceeds the remaining window, the WLAN module 102 does notschedule the corresponding TX and/or RX operation within the remainingwindow and may wait for another available remaining window. Note thatbecause the Bluetooth is guaranteed not to have higher priority TXand/or RX activities within the remaining window, the WLAN module 102 isfree to use this time period, while preventing undesired trafficcollisions. Note also that according to an embodiment of the invention,the WLAN module 102 may comprise a counter to count down a counter valueinitially set to the received estimated remaining time (e.g. 2.5 ms),and determine whether the time required for the corresponding TX and/orRX operation exceeds the remaining window according to the counter valueevery time the TX and/or RX operation is scheduled. Note that beforereceiving information regarding time remaining for a remaining window,the counter value may always be set to zero, meaning that there is no TXand/or RX window that the WLAN module 102 can use. After receivinginformation regarding a remaining window, the counter value may be setto the estimated remaining time and the counter begins to count down thecounter value until the counter value reaches zero.

FIG. 7 shows a flow chart of a method for coordinating the transmissionand reception operations of a plurality of radio modules in acommunications apparatus according to an embodiment of the invention.After receiving the information regarding the remaining window from theBluetooth module 101 (Step S701), the WLAN module 102 determines whetherthe time required for the following TX and/or RX operation exceeds theremaining window (Step S702). When the time required for the followingTX and/or RX operation does not exceed the remaining window, the WLANmodule 102 may schedule the TX and/or RX operation within the remainingwindow (Step S703). When the time required for the following TX and/orRX operation exceeds the remaining window, the WLAN module 102 does notschedule a corresponding TX and/or RX operation within the remainingwindow and waits for the next available remaining window provided by theBluetooth module 101 (Step S704).

FIG. 8 shows another exemplary time chart of the Bluetooth and WLANactivities using a remaining window according to an embodiment of theinvention. According to the embodiments of the invention, the remainingwindow may also be applied when the WLAN module 102 has entered a powersaving (PS) mode to save battery power. After receiving the informationregarding the remaining window (e.g. 2.5 ms) which the WLAN module 102can process, the WLAN module 102 may first estimate the expected PS Polldata exchange time under power saving mode and determine whether theexpected PS Poll data exchange time exceeds the remaining window. Asshown in FIG. 8, when the first expected PS Poll data exchange time T3does not exceed the remaining window, the WLAN module 102 may begin totransmit the PS Poll request to the WLAN AP and wait for the buffereddata. On the other hand, when the WLAN module 102 determines that theexpected PS Poll data exchange time T4 exceeds the remaining window, theWLAN module 102 may not transmit the PS Poll request to the WLAN AP andmay wait for another available remaining window.

FIG. 9 shows another flow chart of a method for coordinating thetransmission and reception operations of a plurality of radio modules ina communications apparatus according to another embodiment of theinvention. After receiving the information regarding the remainingwindow from the Bluetooth module 101 (Step S901), the WLAN module 102 ina power saving mode may estimate the expected data exchange time underthe power saving mode (Step S902) and determine whether the expecteddata exchange time under the power saving mode exceeds the remainingwindow (Step S903). Note that according to some embodiments of theinvention, the expected data exchange time under the power saving modemay be expected unscheduled automatic power saving delivery (UAPSD) dataexchange time or expected PS Poll data exchange time. For clarity, thepresent invention takes PS Poll data as exemplary embodiment forillustration purpose. In addition, the PS Poll data exchange time maybefrom the time of the PS Poll request is transmitted till the time whenACK for acknowledging the reception of the buffered data is transmittedor may be first estimated according to a previous PS Poll data exchangetime. When the expected data exchange time under the power saving modedoes not exceed the remaining window, the WLAN module 102 may begin totransmit the PS Poll request to the WLAN AP and receive the buffereddata from the WLAN AP (Step S904). According to the embodiment of theinvention, after receiving the buffered data from the WLAN AP, the WLANmodule 102 may further check whether the data rate used by the WLAN APto transmit the buffered data is greater than the expected data rate(Step S905). In some embodiments of the invention, the expected datarate may be directly chosen as the data rate used by the WLAN AP inresponse to a previous PS Poll request. According to other embodimentsof the invention, the expected data rate may also be estimated accordingto the received transmission power of the Beacon frames periodicallysent by the WLAN AP. When the transmission power is obtained, thedistance to the WLAN AP may be accordingly estimated, so as to estimatea suitable data rate as the expected data rate. When the data rate usedby the WLAN AP to transmit the buffered data is not greater than theexpected data rate, the WLAN module 102 may increase the estimatedexpected PS Poll data exchange time according to the data rate and theamount of buffered data (Step S906). When the data rate used by the WLANAP to transmit the buffered data is greater than the expected data rate,the WLAN module 102 may decrease the estimated expected PS Poll dataexchange time according to the data rate and the amount of buffered data(Step S907). The corrected expected PS Poll data exchange time may beused for a next time estimation procedure for a next available remainingwindow. On the other hand, when the expected PS Poll data exchange timeexceeds the remaining window, the WLAN module 102 may not transmit thePS Poll request within the remaining window and wait for the nextavailable remaining window (Step S908).

FIG. 10 shows another exemplary time chart of the Bluetooth and WLANactivities using a remaining window according to an embodiment of theinvention. According to the embodiment of the invention, the concept oftransmitting information regarding the remaining window betweendifferent radio modules may also be applied to IEEE 802.11n withAggregated MAC Protocol Data Unit (A-MPDU). With the knowledge ofremaining window provided by the Bluetooth module 101, the WLAN module102 may aggregate a maximum amount of TX data packets to increasetransmission data throughput. As shown in FIG. 10, the WLAN module 102may determine that at most two data packet transmissions and a blockacknowledgement (BA) reception may be performed within the first WLANremaining window. Therefore, the WLAN module 102 may aggregate andtransmit two data packets (Data 1 and Data 2) within the first WLANremaining window. Next, after receiving information regarding the secondremaining window, the WLAN module 102 may determine that at most threedata packet transmissions and a BA reception may be performed within thesecond WLAN remaining window. Therefore, the WLAN module 102 mayaggregate and transmit the next three data packets (Data 3, Data 4 andData 5) within the second WLAN remaining window. Therefore, based on theinformation regarding the remaining window (i.e. the remaining time thatthe WLAN module 102 can use), the A-MPDU may be implemented moreefficiently so as to further increase data throughput thereof

While the invention has been described by way of example and in terms ofpreferred embodiment, it is to be understood that the invention is notlimited thereto. Those who are skilled in this technology can still makevarious alterations and modifications without departing from the scopeand spirit of this invention. Therefore, the scope of the presentinvention shall be defined and protected by the following claims andtheir equivalents.

What is claimed is:
 1. A method for coordinating transmission andreception operations of at least a first and a second radio module in acommunications apparatus, the first radio module communicating with afirst communications device in compliance with a first protocol toprovide a first wireless communications service and the second radiomodule communicating with a second communications device in compliancewith a second protocol to provide a second wireless communicationsservice, comprising: estimating, by the first radio module, timeremaining for the second radio module; receiving, by the second radiomodule, information regarding the estimated remaining time from thefirst radio module; determining, by the second radio module, whethertime required for the operations of the second radio module exceeds theestimated remaining time; scheduling, by the second radio module,operations of the second radio module according to the informationregarding the estimated remaining time received from the first radiomodule; wherein scheduling the operations of the second radio module, bythe second radio module, when the time required for the operations ofthe second radio module does not exceed the estimated remaining time,and, wherein the scheduling step further comprises estimating expecteddata exchange time under a power saving (PS) mode according to anexpected data rate used by the second communications device to transmitdata to the second radio module after receiving the informationregarding the estimated remaining time from the first radio module whenthe second radio module enters into the power saving mode.
 2. The methodas claimed in claim 1, further comprising: not scheduling the operationsof the second radio module and waiting for information regarding anotherestimated remaining time from the first radio module when the timerequired for the operations of the second radio module exceeds theestimated remaining time.
 3. The method as claimed in claim 1, furthercomprising: setting a counter value to the estimated remaining timeafter receiving the information regarding the estimated remaining timefrom the first radio module; and down counting the counter value untilthe counter value becomes zero.
 4. The method as claimed in claim 1,further comprising: wherein when the expected data exchange time underthe power saving mode does not exceed the estimated remaining time, themethod further comprises transmitting, by the second radio module, a PSPoll request to the second communications device
 5. The method asclaimed in claim 4, further comprising: checking whether a data rateused by the second communications device to transmit the buffered datais greater than the expected data rate after receiving the buffered datafrom the second communications device; and increasing the estimatedexpected data exchange time under the power saving mode when the datarate used by the second communications device to transmit the buffereddata is not greater than the expected data rate.
 6. The method asclaimed in claim 4, further comprising: decreasing the estimatedexpected data exchange time under the power saving mode when the datarate used by the second communications device to transmit the buffereddata is greater than the expected data rate.
 7. The method as claimed inclaim 1, further comprising: determining how many data packets at mostcan be successfully transmitted within the estimated remaining timeafter receiving the information regarding the estimated remaining time;aggregating the data packets; and transmitting the aggregated datapackets within the estimated remaining time.